Visible‐color‐tunable light‐emitting diodes (LEDs) with electroluminescent color that changes continuously from red to blue by adjusting the external electric bias are fabricated using multifacetted GaN nanorods with anisotropically formed 3D InGaN multiple‐quantum wells. Monolithically integrated red, green, and blue LEDs on a single substrate, operating at a fixed drive current, are also demonstrated for inorganic full‐color LED display applications.

Through this work, we have elucidated the mechanism of hydroxyl radicals (OH•) generation and its life time measurements in biosolution. We observed that plasma-initiated ultraviolet (UV) photolysis were responsible for the continues generation of OH• species, that resulted in OH• to be major reactive species (RS) in the solution. The density and lifetime of OH• species acted inversely proportional to each other with increasing depth inside the solution. The cause of increased lifetime of OH• inside the solution is predicted using theoretical and semiempirical calculations. Further, to predict the mechanism of conversion of hydroxide ion (OH−) to OH• or H2O2 (hydrogen peroxide) and electron, we determined the current inside the solution of different pH. Additionally, we have investigated the critical criterion for OH• interaction on cancer cell inducing apoptosis under effective OH• exposure time. These studies are innovative in the field of plasma chemistry and medicine.

Semiconductor nanowire arrays integrated vertically on graphene films offer significant advantages for many sophisticated device applications. We report on van der Waals (VDW) epitaxy of InAs nanowires vertically aligned on graphene substrates using metal-organic chemical vapor deposition. The strong correlation between the growth direction of InAs nanowires and surface roughness of graphene substrates was investigated using various graphene films with different numbers of stacked layers. Notably, vertically well-aligned InAs nanowire arrays were obtained easily on single-layer graphene substrates with sufficiently strong VDW attraction. This study presents a considerable advance toward the VDW heteroepitaxy of inorganic nanostructures on chemical vapor-deposited large-area graphenes. More importantly, this work demonstrates the thinnest epitaxial substrate material that yields vertical nanowire arrays by the VDW epitaxy method.

The photocatalytic activity of GaN nanowires was investigated for the use of GaN nanowires as photocatalysts in harsh environments. GaN nanowires with diameters of 20-50 nm and lengths of 4-6 microm were prepared by Ni catalyst-assisted metal-organic chemical vapor deposition. Comparisons of GaN nanowires with GaN submicron dot arrays and thin films showed that GaN nanowires exhibit much better photocatalytic activity, resulting from a high surface-to-volume ratio. In addition, GaN nanowires exhibited good ability to photodegrade organic dye at various pHs, even under strong acidity and alkalinity. The photocatalytic activity of GaN nanowires was also compared with that of ZnO and TiO(2) nanowires.